Electric signal system



Dec. 22, 1931. T. H. THOMAS ELECTRIC SIGNAL SYSTEM Filed April 7. 1927 I HNI un un "la uw,

Patented Dec. Z2, 1931 UNITED STATES PATENT oFFicE" THOMAS THOMAS,OF EDGEVVOOD, PENNSYLVANIA, ASSIGNOR TO TEE WSTING- HOUSE AIR BRAKE COMPANY, F WILMERDING, PENNSYLVANIA, A CORPORATION 0F PENNSYLVANIA Applicationled April 7,

This invention relates to signal systems, and more particularly to an electric signal system adapted for use on railway trains.

The principal'obj ect of my invention is to provide a train signal system in which the engineer by operating one switch device may signal in response to a signal received by the engineer and by Voperating another switch device may at any time transmit al signal to one or more vehicles of the train.

In the accompanying drawings: Fig. 1 is a diagrammatic view of an electric train signal system embodying my invention;` and F ig. 2 a section of the circuit controlling plug switch, on the line 2-2 of F ig. 1.

As shown in the drawings, there is provided on each car of the train aV buzzer or sound producing device comprising an electromagnet l having two magnet coils 2 and 3 and a pivotally mounted armature 4, movable away from the magnet by the spring 5, when the magnet is deenergized, and toward vthe magnet, when the magnet is'energized.

ne terminal of each coil 2 andA 3 is connected to a single train wire 6 and the other terminal of coil 2 is connected to a wire 7, which leads to va contact finger controlled by a plug switch devicecomprising a casing 9 having a tapered bore adapted to receive'a removable switch plug 10. The switch plug 10 is providedv with contact segments 11 and 12.

A manually controlled switch device is pro'- vided on each car of the train andcomprising a casing in which is slidably mounted a contact member 16 provided with contactsy 23 and 24. The contact member 16 is provided with an operating push button 17 and is normally maintained in its upper position, as shown in the drawings, by'a spring 27.

On the'locomotive, there is provided a manually controlled switch devicecompris-V ing a casing in which is slidably mounted a contact carrying member :46 having a ccntact 47, said member being normally held in its upper position by a spring 48. Two buzzers 49 and 50 of the well known type, ,which l operate by making and breaking the electric circuit, are connected in parallel to the train wire 6. The buzzers 49 'and 50 are connectedv Vin ELECTRIC SIGNAL SYSTEM 1927. serial No. 181,715.

vrespectivelyto wires 51 and 53 which lead to contacts in the'switch device 45.

The resistance of the winding 2 is greater than the resistance of the winding 3, and the operating characteristics of the buzzer 49 are such that it will not operate in series with the winding 2, but will operate in seriesV with the winding 3. The operating characteristics of the buzzer are such that it will operate when in series with either the winding 2,01' thewinding 3.

` There are many ways, well known in the art, for constructing and adjusting the buzzers, so that they willoperate in the above manner, such as by varying the resistances of the windings of thebuzzers, by varying the air gap between the magnet and the arinature or pole `piece of the buzzer, by varying thestrength of the armature retracting sprin g of the buzzer, by varying the number of turns of the windings of the buzzers, or by a combination of two or more of the above.

An additional switch device may be provided similar to the switch device 45 and coinprising a casing 18 containing a slidable coni tact member 19 provided with a contact 20, a spring 21 acting on the member 19 and tend- 0f to hold same in its upper position.

,ln operation, a plug lO'is inserted in the switch casing 9 by a trainman on each vehicle ot the train whereit is desired to receive signals originating with the engineman.

If the engineman wishes to signal ka station on the train, he depresses the contact Vmember 46. This opens a circuit from the ground 22 through the contact 20 of the switch the train wire 6, through magnet coil 2, wire `7cont'act 11 in the plug switch device, wire 34, battery 35, wire 43, contact 12, and wire 39 to ground at 40. The buzzer 50 on the loco motive will then be caused to operate by cur- `rent supplied through the closed circuit from v the source of current 35 on the car, and since the buzzer 5() acts to make and break the circuit, tae circuit vill likewise be made and broken through the magnet coil 2, so that the armature 4 will be vibrated, due to the alternate energization and deenergization of the magnet 1 and the vibration or the armature serves as a signal on cars in which the plug 10 is inserted.

rlhe operation of the buzzer 50 on the locomotive also indicates to the engineman that the apparatus is working properly and that a signal is being given on cars oi the train.

When a trainman desires to signal the engineman, he presses down on the button 17 of the switch device l5 and thereby closes a circuit from the ground 40, through contact 23, wire 3S, battery 35, wire 34, contact 24, wire 32 magnet coil 3, to train wire 6.

The magnet coil 3 is of low resistance as compared with the coil 2 and suiiicient current will llow through the buzzer 49 to cause saine to operate so as to signal the engineman, the circuit being normally closed from train wire G to ground at 22 through the contact 47 of the switch device 45 and the contact 2O of the switch device 18.

The buzzer 49 in operating will make and break the circuit through the magnet coil 3, so that the armature 4 is caused to vibrate and thus indicate to the trainman that a signal is being properly transmitted to the engineman.

It will be noted that a circuit is normally closed through the buzzer 49 and the magnet coil 2 by way of wire 7, contact 11, wire 34, battery 35, wire 43, contact 12 and wire 39 to ground at 40, but the coil 2 is of such high resistance that even though all the plugs 10 on the train should be inserted, there will not be sufficient flow of current through the buzzer 49 to cause same to operate.

It will also be noted that a trainman may signal the engineman by operation of the switch device 15, regardless of whether or not the plug 10 is inserted in the plug switch device 9.

It the trainman has signalled the engineman and the plug` 10 is not in place, he may receive a signal from the engineman by holding the button 17 depressed. The engineman may then signal the trainman by depressing the contact member 19, so as to open the circuit from the train wire 6 through 4the buzzer 49 to ground at 22.

The switch 45 could not be satisfactorily used under the conditions set forth, because although when the plunger 46 is depressed, the circuit through the wire 51 is momentarily opened, the circuit is again immediately closed through the line 53 to the ground 57. When, however, the plunger 19 is depressed,

Ythe circuit remains open. so long as the plunger is depressed, so that the circuit is definitely deenergized long enough to ensure that the coil 3 will be deeneregized and thus produce a definite pause in the operation of the signal device l.

The result is that the buzzer 49 will cease to operate and the coil 3 will remain deenergized, so that the armature 4 will stop A rectilier 69 or other means for preventing the How ot current except in one direction, may be interposed in the circuit wire 34, so that in case the voltage of the battery 35 should be in excess of that on another car, there will be no possibility ot a reverse 'flow olI current from the excess voltage car back through the batteries of other cars where the voltage is less.

` Having now described my invention, what I claim as new and desire to secure by Letters lbatent, is

1. In an electric train signal system, a train signal circuit, a source ot current connected in said circuit, a signal device on one vehicle ot the train having two windings with different resistances and connected in said circuit, means for locally closing the circuit through one winding, a manually operated switch device on said vehicle for closing the circuit through the other winding, an automatic make and break device in said circuit on another vehicle of the train responsive only to current tlow through one oi' said windings, another automatic make and break device in said circuit responsive to current iiow through either one of said windings, a manually operated switch device for locally closing the circuit through either ot said make and break devices, and another switch device for making and breaking the circuit through one of said make and break devices.

2. In an electric train signal system, a train signal circuit, a source of current connected in saidV circuit, avsignal device having two windings connected in said circuit, one of which is of lower resistance than the other, means for locally closing the circuit through said windings and including said source of current, two automatic circuit make and break devices connected in series with said windings, one of which is responsive only to current flowing through one ot said windings and the other responsive to current owing through either of said windings, and two manually operated switch devices, one for closing the circuit through either of said make and break devices and the other for opening and closing the circuit only through one of said make and break devices. A

3. In an electric train signal system, a train signal circuit, a source ot current connected in said circuit, a signal device having two windings connected in said circuit, one oi which is 'of lower resistance than the other.

means for locally closing the circuit including the source of current through the higher resistance winding, a manually operated switch for locally closing a circuit including the source of current through the other wind ing, two automatic Circuit. make and Abreak devices connected in series with said windings, one of said make and break devices being such that it responds to current flow through either winding and the other make and break device being such that it responds only to current flow through the winding having the lower resistance,V and two manually operable switch devices, one having positions for locally closing the circuit through either of said make and break devices, vand the other for opening and closing the circuit through th-e make and break device which is responsive only to current fiow'through the low resistance winding.

In testimony whereof I have hereunto set my hand. l

THOMAS H. THOMAS. 

